1. Field of the Invention
The present invention relates to a personal computer or the like with a light source controller which is capable of turning the light source for a display apparatus on and off.
2. Description of Related Art
Recently various embodiments of a word processor or a personal computer, which has a liquid crystal display (LCD) apparatus with an auxiliary light such as a backlight unit, have appeared on the market. Typically, the LCD apparatus consists of transmission type LCD which has electro luminescence (EL) unit as a backlight on the backside. In the word processor or the personal computer, light ON/OFF control is performed upon an ON/OFF operation of a power source switch.
The above arrangement poses no problems in a personal word processor or a personal computer in which operating power is obtained from an external commercial power source. However, the following problems are posed in a compact personal word processor or a personal computer which is reduced in size and weight so as to be easily carried, and is driven by a built-in battery so as to be easily used at any place e.g., a notebook size or pocketbook size. In the above-described arrangement, since the backlight is kept ON while the power switch is ON, the power consumption in a normal operation period is large. Still more, a printing unit or a floppy disk drive (FDD) which is attached in the word processor or the computes requires large power consumption. Therefore, in order to allow long-time use of the word processor or the computer, a large-capacity battery, which has a large size and a heavy weight, is conventionally required. This imposes great limitations on reduction in size and weight of the word processor or the computer. In addition, maintaining the backlight ON, even when an operation is interrupted in the process of processing, inevitably wastes the battery power.